During a procedure to retrieve an ovum from an ovary of a human or an animal, generally, a tissue collection needle is attached to an ultrasound probe, and the tissue collection needle is used to puncture the body so that the needle arrives at the ovary under ultrasound and echo imaging. According to the difference in the method of inserting the needle, ultrasound-guided ovum retrieval is classified into transvesical ovum retrieval using an abdominal probe, transvaginal ovum retrieval using an abdominal probe or a transvaginal probe, and transurethral ovum retrieval using an abdominal probe. Currently, the transvaginal method is most commonly adopted among the ultrasound-guided ovum retrieval techniques, because, for example, the puncture distance is short, which avoids injury to the skin, and local anesthesia is effective.
Ultrasound-guided ovum retrieval has been performed by repeating operations of puncturing a follicle with a single-needle type ultrasound needle, infusing lavage fluid into the follicle with a syringe, and then aspirating the follicle with another syringe to retrieve an ovum. However, in this method, the sharpened edge of the needle moves or the lavage fluid flows backward or leaks during the operation of exchanging one syringe for another syringe, and so there were disadvantages that it takes time to retrieve an ovum and also the yield of such ovum retrieval is low. Afterward, a double-lumen tissue collection needle including an outer hollow metal needle provided with a sharpened edge at the tip thereof and an inner hollow tube installed inside the outer needle has been developed so that it is ensured that the inner diameter of an ovum retrieval route is large enough to allow ova to pass through the route and the flow rate through a lavage route is also sufficient (Japanese Laid-Open Patent Publication Nos. 2001-190560 and 2003-126106).
Generally, not only such tissue collection needles but also needles that are to be inserted into the body while their position being confirmed by echography are provided with an echo guide that reflects ultrasound waves on the external surface near the tip portion of the needles. The echo guide may include, for example, a surface having microscopic asperities formed by grinding and slitting or sandblasting. The surface area on which the echo guide is formed is small so that the echo guide does not affect puncture and insertion of the needles. If a very high-precision ultrasound imaging system is used, needles can be imaged even without such an echo guide. However, only a portion of the echo guide can be imaged by a common general-purpose ultrasound imaging system. Accordingly, when a needle is fixed, the needle cannot be imaged in some cases depending on, for example, the relationship between the orientation of the needle and the scanning direction of an ultrasound probe. Therefore, it is considerably difficult to reliably know the position of a very fine needle tip by echography.